Phosphorus-containing organic compounds



Patented Aug. 18, 1953 PKQSFHGRUS-CONTAINING ORGANIC COMPOUNDS Gilbert Spencer- Earthy, Fulbourn, and Denis Willi in Pound, Harston, England, assigno'rs to Pest control Limited, Boum,.-Eng1ana, a British company Nognraw-i g Application August 195'1, Serial No.; 242,995. In Great Britain Se tember 7,

solates. (01. zoo-.3 9

I "This invention relates to new' pnospnoruweontainin organic compounds and: processes for their manufacture. 7

it is an object or this invention to" provide new pounds and processes fontn'eirnann ure.

It is a further ob ect or this invention to pro= v'i'de certain novel ph'osphoruswontainingorganic compounds which are particularly useful as s'y"s= te'n jio insecticides". v v

The compound of the present invention are pnosphorus oontainin organic compounds containing less than eleven carbon atoms in the molecule of tire-general formula:

RRN

RUE/UN where R and R are the same difffiit are each a hyorogenatoni or ik lgroiip containing less than one carbon atoms aiid R and R' are the same diflerent '"reeaeh alkyl' group containing less" fi ve carbon atoms.

These new compounds are phosphors-i az'id'es and it is somewhat s'fii'pr th" pounds can be formed of atan y tate aresuaic'iently stable for practical use. H

A representative compound of the present iii-- ventior'i is bis' diiiiethylaifi "'o aiido-phosp me oxide [(CHa'HNlaPOENm rnisoomponiid is very stable in neutral adu'oussbliitwn and behaves as a systemic insect ice. Furthermore, with regard to acid and alkaline hydrolysis, the orh pound is more stable than the corresponding fluoride.

Another representative compound of the present invention is dimethylamino i'n'ono iisopropvl amino-azido-phosph o'xiae, is particularly efiective'as a s Yni'c insecticide. 4 v

This azido oompon n'a is rather more s'table in water both towards acids and alkalies than the corresponding fluoro compound. It has also rather more tendency to partition into organic solvents from water and oanibe salted "out "of aqueous solution as a substantially "pure hase by means-ofsodium-chloride. The substa'iiti 13; pure liquid, after drying in a vacuum "desiccator over anhydrous calcium chloride, was not subjected to di'stillationbut was maintaineiiat 1:60 While small gun owder charges e exploded above it so that incandescent t cles were proje'ct'ed into the liquid. No "lgnlfid n occurred. Further, a 50% solution 'intenzene "ignited on cotton wool comparison "with "a 'siinfla'r 2. treatment of pure benzene. The 'conflagration was no more violent in the case of the former solution. The liquid azido phosphine oxide isnot' therefore hazardous'ly explosive.

The compounds of the present invention can be made in good yield from the corresponding onlorophos hine oxides by agitating. with a conc'entrat'ed aqueous solution of a water-solub'le met-a1 a'zide, preferably sodium azide or an aqueone or organic-aqueous solution or an azi'de of an organic base.

They ma also be made by reacting the corresponding chlorophosphine oxides with hydrazine to form a compound of general formula (RR'N?.'(R"R':'N) PD.NH.NH2 which is then reacted with "nitrous acid'in aqueous solution.

'Thus, the present invention also includes a process for the manufacture of phosphorus-eontair'iing organic compounds containing less than eleven carbon atoms in the molecule 'Of the geneial formula:

fi/IRII'IN Where R and R" are the same or different and are each a hydrogen atomor an: alkyl group containing less than five carbon atoms andv R and R are the same or different and are each an alkyl group containing less than five carbon atoms, wherein a compound of the general formula:

1on Cl is reacted with a concentrated aqueous solution of a water soluble metal azide, preferably sodium az'ide, or an aqueous or organic-aqueous solution of an azid'e of an organic base.

The present invention further includes :a process for the manuiacture of phosphorus-containing organic compounds containing less than eleven "carbon atoms the =m016tliile 0f the :general formula:

RRN

ProeNz' jRfi/FRIUN Wh''r'e R "and R are the same or different and are each a hydrogen atom or an alkyl group containing less than five carbon atoms, and R and R""' 'arethe same or different and are each an 'alkyl group containing less than live carbon atoms, wherein a compound of the general formula:

RRN o is reacted with hydrazine to form a compound of the general formula:

which is then reacted with nitrous acid in aqueous solution.

In carrying out the two above processes it is not necessary to start from the chlorine compound of the above-quoted general formula in its pure, isolated form. A start may equally well be made from a reaction mixture of an amine and phosphorus oxychloride containing the said chlorine compound, and this reaction mixture may be treated with the azide solution or with the hydrazine.

Example 1 Bis dimethylamino chloro phosphine oxide was prepared by the addition of four molecular proportions of dimethylamine dissolved in carbon tetrachloride to one molecular proportion of phosphorus oxychloride in carbon tetrachloride. Dimethylamine hydrochloride was filtered off and the desired compound purified by fractional distillation of the filtrate.

10 gms. of this product was added, with agitation and cooling, to gms. of sodium azide dissolved in 25 cos. of water during a period of 30 minutes. The mixture was stirred at 15 C. for one hour and then extracted with two successive portions of 25 ccs. of chloroform to obtain the desired product free from sodium chloride and organic electrolytes derived from side reactions. To the combined chloroform extracts 50 ccs. of water were added and the mixture distilled under a pressure of 20 mms. mercury to remove the chloroform, leaving a clear aqueous solution of volume 41 cos.

The resulting solution gave only a trace of amine on distillation with alkali and only a very slight precipitate with silver nitrate. After refluxing an aliquot in N hydrochloric acid for 30 minutes and then distilling from excess alkali, the distillate contained amine estimated by titration with hydrochloric acid to be equivalent to 1.47 gm. equivalents per litre of the original solution. No more amine was produced from a second aliquot which was refluxed with hydrochloric acid for 60 minutes, hydrolysis to amine being thus shown to be complete.

An aliquot Was refluxed with N sodium hydroxide for 30 minutes and azide ions determined, in comparison with standards, by colorimetric estimation of the compound of azide and ferric ion in solution. Combined azide was thus found to be equivalent to 0.72 gm. equivalent per litre of original solution. A longer period of alkaline hydrolysis did not increase the yield of azide ion.

Phosphoric acid was determined by destructive hydrolysis and oxidation of an aliquot of solution containing less than 5 mgm. of the product in order to avoid explosion hazards by refluxing with 60% perchloric acid, after which excess perchloric acid was evaporated off and residual phosphoric acid determined colorimetrically by the molybdenum blue method (of. Allen, Biochem. Journ. (1940), 850). Phosphoric acid 4 corresponded to 0.73 gm.-mols. per litre of original solution.

These concentrations are in the ratio of 2:121 within experimental error and substantiate the constitution expected for the product. The concentration corresponds to a yield of 45% in the reaction between the bis(dimethylamino) chlorophosphine oxide and aqueous sodium azide.

A specimen of the aqueous solution made from phosphorus oxychloride containing radio-active phosphorus was found to give a partition ratio between chloroform and water of approximately 35:1 infavour of chloroform at C. The radioactivity was still almost entirely transferred to the chloroform layer when the aqueous solution was again shaken with chloroform after standing for three weeks. No evolution of nitrogen was detected. The solution is, therefore, one of the substantially pure compound which is stable at ordinary temperature.

Aqueous solution diluted to 0.1% was sprayed on chrysanthemums and allowed to dry. Untreated chrysanthemum leaves bearing live specimens ofthe aphids macrosiphoniella and coloradoa, were held adjacent to leaves of the treated plant. Those aphids which transferred themselves died after a few hours while those which remained. on the untreated leaves survived. In another experiment, a 0.1% solution Was applied to the roots of potatoes infested with the aphis myzus persicae and after a period from 12 to 72 hours according to situation the aphids were killed, showing that the insecticidal compound is translocated by the plant.

Example 2 To 76.5 gms. of phosphorus oxychloride in 300 cos. of trichlorethylene was added with agitation and cooling 118 gms. of isopropylamine, the reaction temperature being kept at 20i2 C.

gms. of sodium azide dissolved in 70 cos. of water was added, and agitation and cooling continued for one hour. The solvent was removed by distillation at 10 mms. and -60" C. petroleum ether added to the residue. The crystalline product was filtered ofi.

Analysis of an aqueous solution of the crystalline product was carried out as in Example 1 by hydrolysis in acid followed by distillation of amine from alkali, by hydrolysis in alkali and colorimetric estimation of azide ion and by colorimetric estimation of phosphoric acid after destruction of a small sample with perchloric acid. This indicated that the product was substantially pure bis(mono-isopropylamino) -azidophosphine oxide.

Found: isopropylamine 58.2%, azide 19.8%, phosphoric acid 47.6%. Theory: 57.5, 20.5 and 47.8% respectively.

Biological tests similar to those described above with a solution of this material indicated that it also had power to kill aphids after absorption into plants.

Example 3 oxide had a boiling point of 118 C. at about.

1.5 mm. of mercury, and a melting point of about 30C. 21 gms. of sodium azide and 6.5 gms. of sodium bicarbonate were agitated with ccs. of

water and 50 gms. of the chloride added during 50 minutes. The temperature was raised to 40 C. and maintained there for 40 minutes. The top organic layer was separated and washed once with a, small volume of brine.

The product was dried by standing in a vacuum desiccator containing calcium chloride.

5 gms. of the product were made up to 100 ccs. with water. The resulting solution gave only a trace of amine on distillation with alkali and only a very slight precipitate with silver nitrate. After refluxing 20 ccs. in N hydrochloric acid for 30 minutes and then distilling from excess alkali, the distillate contained amine which estimated by titration with N hydrochloric acid, required 10.3 ccs. for neutralisation, amounting to 0.52 equivalents per litre of the original solution. No more amine was produced from a second aliquot which was refluxed with hydrochloric acid for 60 minutes, hydrolysis to amine being thus shown to be complete.

20 cos. of the above solution was refluxed with N sodium hydroxide for 30 minutes and azide ion determined, in comparison with standards, by

, colorimetric estimation of the compound of azide and ferric ion in solution. Combined azide was thus found to be equivalent to 0.26 gm. equivalent per litre of original solution. A longer period of alkaline hydrolysis did not increase the yield of azide ion.

Phosphoric acid was determined by destructive hydrolysis and oxidation of 0.2 cos. of the above solution (containing only mg. of the product in order to avoid explosion hazards) by refluxing with 60% perchloric acid, after which excess perchloric acid was evaporated off and residual phosphoric acid determined colorimetrically by the molybdenum blue method (cf. Allen, Biochem. Journ. (1940), 850). The phosphoric acid corresponded to 0.26 gm.-mol. per litre of original solution.

An aqueous solution of the compound diluted to 0.005% when sprayed directly on chrysanthemum leaves bearing live aphids killed all the aphids within 24 hours. When a 0.05% solution was used the aphids were all dead in one hour. An aqueous solution diluted to 0.05% was sprayed in chrysanthemums and allowed to dry. Untreated chrysanthemum leaves bearing live specimens of the aphids Macrosiphoniellw sanborni and Coloradoa. rufomaculata were held adjacent to leaves of the treated plant. Those aphids which transferred themselves died after a few hours while those which remained on the untreated leaves survived. In another experiment, a 0.1% solution was applied to the roots of potatoes infested with the aphis myzus persicae and after a period from 12 to 72 hours according to situation the aphids were killed, showing that the insecticidal compound is translocated by the plant.

What we claim is:

1. New phosphorus-containing organic compounds containing less than eleven carbon atoms in the molecule of the general formula:

RRN

P.O.Na

BURN/N where R is selected from the group consisting of alkyl groups containing less than five carbon atoms and hydrogen, R is an alkyl group containing less than five carbon atoms, R" is selected from the group consisting of alkyl groups containing less than five carbon atoms and hydrogen and R is an alkyl group containing less than five carbon atoms.

2. Bis-dimethylamino-azido-phosphine oxide.

3. Bis(mono-isopropylamino) -azido-phosphine oxide.

4. Dimethylamino-mono isopropylamino azido-phosphine oxide.

5. A process for the manufacture of phosphorus-containing organic compounds containing less than eleven carbon atoms in the molecule of the general formula:

RRN

P.O.Na

RIIRII/N where R is selected from the group consisting of alkyl groups containing less than five carbon atoms and hydrogen, R, is an alkyl group containing less than five carbon atoms, R" is selected from the group consisting of alkyl groups containing less than five carbon atoms and hydrogen and R is an alkyl group containing less than five carbon atoms, which comprises reacting a compound of the general formula:

R"RN/ o1 with a concentrated aqueous solution of a watersoluble metal azide.

6. A process for the manufacture of phosphorus-containing organic compounds containing less than eleven carbon atoms in the molecule of the general formula:

R/IRII/N where R is selected from the group consisting of alkyl groups containing less than five carbon atoms and hydrogen, R is an alkyl group containing less than five carbon atoms, R" is selected from the group consisting of alkyl groups containing less than five carbon atoms and hydrogen and R' is an alkyl group containing less than five carbon atoms, which comprises reacting a compound of the general formula:

P RRN/ Cl with a concentrated aqueous solution of sodium azide.

GILBERT SPENCER HARTLEY. DENIS WILLIAM POUND.

References Cited in the file of this patent Sidgewick: Organic Chemistry of Nitrogen (1937), Pp. 374 to 375. 

1. NEW PHOSPHORUS-CONTAINING ORGANIC COMPOUNDS CONTAINING LESS THAN ELEVEN CARBON ATOMS IN THE MOLECULE OF THE GENERAL FORMULA: 